Dear authors,

I have read the two reviews, your responses and your cover letter. Overall, I believe most comments have been addressed satisfactorily, but below I add my interpretation of points raised where I felt a further revision is required.

The main contribution of your study appears to provide evidence of major small-scale variation in hydrological response in this environment due to the effect of solar exposure on permafrost and vegetation and demonstrate that these can be accounted for using improved sub-grid parameterization that recognises those landscape contrasts.

I had some trouble understanding the methodology until I realised that the ‘fine resolution landscape model’ is, in fact, a ‘model’ of a very different nature than the VIC model used in the simulations. Please revise the terminology used to remove this ambiguity. To me, it would indeed better be described as a ‘(subgrid) parameterization method’ or similar. As an aside, unlike Referee 2, I would think ‘parameterization scheme’ would also be acceptable, since, as I understand it, you use the grid cell tiling to describe the distribution of sub-grid variability.

Given the objective, I agree that comparison with a global parameter data set is appropriate. However, referee 1 is correct that you compare to no more than two streamflow records for very small catchments, and that this makes for a very limited validation. The runoff contrast between the two catchments is strong, and your method reproduces it, but given the sample of 2, you cannot entirely discount the possibility that that is fortuitous. I accept that these may well be all the streamflow data available to you, but you should be a bit more circumspect in the phrasing of your conclusions. Also, note that any second phase of this research is not relevant to the results presented here.

Both reviewers comment on the interpretation of the Nash-Sutcliffe criterion. I accept your response, but I even wonder whether this is a well-chosen measure of success given that it is very sensitive to bias? I would think perhaps a better test would be whether your parameterisation can reproduce the strong relative contrast in runoff behaviour between the two catchments?

I agree with Referee 2 that the discussion of ET and soil moisture are too detailed. Given the objective of your study, they provide no means of validation or circumstantial support, as far as I can see. I can understand you might wish to provide some short commentary on how the model reconciles the difference in runoff between the two catchments or contrasting landscape components with the other water balance terms, but that can easily be done with a small table or histogram, with a very brief discussion. As it is, it digresses from the main point of your study and, importantly, lacks the empirical support to show it reflects real-world processes. Pls reduce this section.

I also have some further minor comments:

P5, l.17) “Hence” – this is only true if the relationship between parameter and flux is a nonlinear one; if it is linear then parameters can be averaged.
P7, L 3) Pls state resolution
Fig. 1) Pls indicate in caption how the permafrost was mapped.
Fig 5) flow duration curves might also be insightful?

Overall, I consider it minor revisions, as they relate to text and presentation rather than substance.


Please submit, along with the revised manuscript, point-by-point responses, linked to a list of changes in the revised manuscript. The latter can also be a tracked-changes version of the revised manuscript.

Thank you for your response and revisions. I consider the resulting m/s to be suitable for publication.